Film developing apparatus



June 28, 1887. E LA H 2,085,188

FILM DEVELOPING APPARATUS Filed April 26, 1935 INVENTOR ffiWl/V GZ/FLACH ATTORNEY Patented June 29, 1937 UNITED STATES PATENT OFFICE FILM DEVELOPING APPARATUS Application April 26, 1935, Serial No. 18,299 In Germany April 30, 1934 4 Claims.

This invention relates to the continuous processing of photographic film, and has for its principal object the provision-of an improved film processing apparatus whereby the film is effec- 5 tively brought into contact with different parts of the developing fluid.

It is customary-to pass the film sequentially over rollers through the baths required for its treatment. Since such baths are incidentally exhausted and consumed a steady change in concentration of the baths takes place. 1 Such change in concentration may, to a certain extent, be compensated by gradual replenishing with fresh solutions. However, it is not readily possible? in this '15 manner to insure a reliable and constant effect. -If unspent solutions being as fresh as feasible are to be used, this means a large consumption of chemicals. If the developer is to be employed'under optimum conditions from an ecofilm is drawn or pressed throughsuitably proportioned piping, for instance, if pressure is applied, such shortcomings and inconvenience as is usually attendant upon the threading or insertion of the film will be avoided. The inlet or 3 entrance point of the film into such a pipe is at the same time the outlet for the spent solution, while the outlet polnt'for the film in the pipe is at the same time the inlet point for fresh solution.

chemicals are concerned, the solution will leave in a state near exhaustion. The treatmentof the film, therefore, takes initially place with practically spent solution, this being admissible and practical .in this instance inasmuch as the emulsion of the film at this point still possesses.

its full reaction powers. The fresh solution, on the contrary, acts upon an emulsion which is nearly completely treated so that the chemical reaction will be safely terminated.

Instead of one long pipe for each solution, it is possible also to use several smaller pipes inasmuch as it is somewhat diflicult to convey the film through unduly long pipes. These smaller The rate of speed of the two opposite v movements should preferably beso regulated that, especially where high grade and costly pipes are preferably connected in series. The

counter-current principle is in this case just as readily practicable as if a single long pipe were employed. For the various developing stages and solutions, the film may be made to travel sequentially through different pipes or groups of pipes. It will be evident that the pipes may contain any desired curvatures or bends provided that it is feasible by the aid of rollers .and the like to convey the film in a satisfactory manner.

Itis also possible to .employ a plurality of seriated vats or troughs rather than groups of pipes. Inside each vat developing may be produced in the same manner as in the single vat process according to the prior art, the film'being ,conveyed in each vat over suitable rollers several times in opposite directions. However, since the solution flows continuously from the first to the last vat in the series the film travels in opposition to the sense of travel of the liquid.

If thelength of stay of the film in one of the various baths traversed by the film consecutively is to be altered without altering the rate of travel of the film or the rate of fiow or velocity of the solution, then, according to another object of this invention, the height or level of the liquid or bath inside the vat or the pipe may be changed so that the film is caused to travel, say, for a shorter period through a diminished volume ofliquid.

.Under certain circumstances it may also be advisable to use different rates of fiow for the solutions. Thus, cheaper solutions may be caused to fiow through at a higher rate of veloc- 'ity than'more expensive ones.

The invention will be better understood from the following description when considered in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Referring to the drawing,

Fig. 1 is a sectional view of a continuous film processing machine constructed in accordance with the invention, and

Fig. 2 is a sectional view'of a suitable form of film conduit.

Referring to Fig. l, the film l is conveyed over the conveyor roll 2 in the direction of the arrow 3 through the pipe system 4. Inside the latter is the developer which, according to thisinvention, is conducted therethrough in a: contrary to the direction of travel of the film, that is to say, in the direction indicated by the: arrow 5. The admission and supply of the liquid and the conduction thereof may be insured by suit- -able conveyor means I (not shown),- suchfl-as' the film may be thrust or pressed through the piping, and that the volume of liquid required for insuring development is comparatively small. 15 Instead of liquid solutions, it is also possible to use gaseswithout departing from the scope of this invention.

I claim: 1. A continuous film processing macmne in 20 cluding a plurality of conduits curved at the bottom and open at the top, pipes interconnecting the upper ends of said conduits for carrying a developing liquid from one conduit to another, and a roller above the liquid level arrangeclto 25 guide afilm from one to another of said conduits.

2. A continuou'sfilm processing machine including a plurality of U-shaped conduits having V-shaped sides for contacting only the edge of the film, pipes interconnecting the upper ends of said conduits for carrying a treating liquid from one to another of said. conduits, and means above the liquid level at the upper ends of said conduits for moving said film from one to another of said conduits.

3. A continuous film processing machine including a plurality of U-shaped conduits having V-shaped sides for contacting only the edge of the film, pipes interconnecting'the upper ends of said conduits for carrying a treating liquid from one to another of said conduits, and means above the liquid level at the upper ends of said conduits for moving said film from one to another of said conduits against the current of said liquid.

4. A continuous film processing machine including a plurality of conduits having v-shaped sides for contacting only the edge of the film,-

pipes interconnecting said conduits for carrying a. treating liquid from one to another of said conduits, and means above the liquid level for moving said film from one to another of said conduits against the current of said liquid.

ERWIN GERLACH. 

